Passive fire resistant system for filling a space or gap confined by construction elements and a prefabricated multilayered structure of such a system

ABSTRACT

A passive fire resistant system for filling a space or gap confined by construction elements, for resisting the spread of a nearby fire through the space or gap, wherein the system comprises: at least two first layers of a first, material which comprises a fire resistant elastomeric foam raving a closed cell structure; and at least one second layer of a second material sandwiched between two first layers, the second material comprising a polymer and each second layer having surfaces which, as an initial response to a rise in their temperature from room temperature, exhibit a transition into an adhesive, the first and second layers extending parallel to each other, the second material being stiffer than the first material.

The invention is related to a passive fire resistant system for filling a space so that the system resists the spread of a nearby fire through the space. The invention is further related to a prefabricated multilayered structure of such a system for filling spaces or gaps in constructions. The word “passive” intends to reveal that the system does not need to be triggered by anything else other than a rise in temperature due to a nearby fire.

BACKGROUND OF THE INVENTION

Many constructions, offshore constructions and onshore constructions, comprise purposely designed spaces or gaps in or between construction elements. These spaces or gaps may be formed between ceilings and walls in onshore constructions and facilitate positioning the construction elements relative to each other. The spaces or gaps may have the function of thermally or sound-wise insulating the construction elements from each other. Particularly in steel constructions (both onshore and offshore) such spaces or gaps may also have been designed to allow for differences in thermal expansion between the construction elements. This applied more in particular to so-called “blast-walls” and floors. The spaces and gaps may be relatively large and do sometimes need to be filled by an element that still provides some mechanical stability. Examples can be found between modularly built living units as placed on oil rigs or as used for expanding jails. Such spaces or gaps are designed to be kept free from cables and/or pipes etc. Such a space could, however, be formed by a coaming in a steel construction such as an offshore oil rig or onboard of a vessel, or a window-type space in a stone or concrete wall. It is possible that such a space or gap allows in essence for future incorporation of further infrastructural facilities such as electricity cables, sewage pipes etc. However, it is also possible that such spaces or gaps are always intended to be present and are never intended to be used for transit of further infrastructural facilities. In any case, all such spaces or gaps referred to above are normally required to be sealed off, so that in case of a nearby fire, the fire is not likely to spread through such spaces or gaps throughout the construction. Hence, systems are available for sealing such spaces or gaps in the prior art, also referred to as “openings”.

WO2004/096369 describes a fire resistant material based on an elastomeric foam with a substantially closed-cell structure in which a foam, at least crust-forming fire retardant material and a pH-neutralized graphite material are incorporated. As shown in FIGS. 9 and 10 of WO2004/096369 and as explained in the accompanying description of those figures, particularly page 15 and 16, this material expands upon exposure to heat in the direction which is not directly exposed to the nearby fire. As a result thereof, the sealing is lengthened in a direction in which the temperature decreases. As a result, the material offers longer protection against the effect of fire and/or extreme heat. This material is very suitable for relatively small spaces or gaps. Where the space or gap is large, it cannot offer much mechanical stability.

Particularly, WO2005/078884 describes such a system for sealing an opening in a wall, using first and second fire resistant parts for at least temporary fire resistant sealing of such an opening. The first parts are manufactured substantially from a fire resistant rubber and/or fire resistant thermal plastic. The second parts are manufactured from a fire resistant material based on an elastomeric foam. The first parts are sleeve shaped and comprise a slit for the purpose of being able to place it around the transport device such as a cable, conduit or tube. This system is exclusively dedicated to openings through which a cable, conduit or tube has been fed through. In other words, this system is not suitable for the spaces and gaps for which this disclosure provides a fire resistant system.

OBJECT OF THE INVENTION

It is an object of the invention to provide an improved passive fire resistant system for filling a space or gap for resisting the spread of a nearby fire through that space or gap.

It is a further object of the invention to provide a system that maintains for a much longer period of time during which the system is exposed on one side to a significant rise in temperature, the low temperature at the side which is not exposed to the nearby fire.

It is a further object of the invention to provide a system which demonstrates after cooling down of the side exposed to a nearby fire, water tightness of that system against a stream of water used for extinguishing the fire.

SUMMARY OF THE INVENTION

The invention provides a passive fire resistant system for filling a space or gap confined by construction elements, for resisting the spread of a nearby fire through the space or gap. The system comprises at least two first layers of a first material which comprises a fire resistant elastomeric foam having a closed-cell structure. The system further comprises at least one second layer of a second material sandwiched between the two first layers. The second material comprises a polymer and each second layer has surfaces which, as an initial response to a rise in their temperature from room temperature, exhibits a transition into an adhesive. These first and second layers extend parallel to each other. The second material is stiffer than the first material.

Without wishing to be bound by any theory, it is strongly believed that as a result of a nearby fire, i.e. due to a rise in temperature, initially the surfaces of the second material become adhesive so that the first and second layers at their contact surfaces stick firmly to each other. Although, as a consequence of the rise in temperature, the gas pressure in the closed cells of the elastomeric foam increases, expansion of these closed cells is suppressed by the adhesion of the elastomeric foam close to the second layers to the second material. This suppression is possible as the second material is much stiffer than the first material. The much stiffer second material imposes thus a counterforce onto the expanding elastomeric foam. As the expansion of the closed cells is suppressed, a bursting pressure of these cells is not reached. The insulating capacity of the fire resistant system is consequently maintained for a larger period of time. As, initially, the expansion of the fire resistant elastomeric foam is suppressed, and insulating properties are well maintained, the passive fire resistant system remains at a side that is not exposed directly to a nearby fire, much longer in its original state. As the temperature deeper into the multi-layered structure remains low, also the mechanical stability offered by the system, and further elaborated on below, continues to be unaffected.

In an embodiment of a system according to the invention, the at least one second layer is adhesively sandwiched between two first layers by adhesive contact of the second layer with each of these first layers. Advantageously, at least three layers can as one unit rapidly and conveniently be placed in the space that needs to be filled with the passive fire resistant system. It is even possible to make a multi-layered structure of first and second layers in a size such that by placement of one unit of such a multi-structure the space is directly filled up with the passive fire resistant system.

In an embodiment of a system according to the invention, each first layer is sandwiched between two second layers of the second material. This has the advantage that a number of the outer layers of the passive fire resistant system are always of the second material. Upon increase of the temperature, the outer surfaces of these second layers will exhibit the transition into an adhesive and as such adhere the passive fire resistant system as placed in the space against the inner wall of that space. This will provide an additional “cage” in which the passive fire resistant system will then be held, providing an additional counter-pressure against expansion of the elastomeric foam. In other words, it further contributes to maintaining the original state of the passive fire resistant system in that space, particularly maintaining the closed state of the cells in the elastomeric foam.

In an embodiment of a system according to the invention, each first layer is adhesively sandwiched between two second layers of the second material by adhesive contact of the second layers with the first layers. Also in this embodiment, it is advantageous that the outer layers are already fixed to the main body of layers so that the passive fire resistant system for filling a space can be considered a fully pre-fabricated unit that significantly reduces the time needed for installing the passive fire resistant system in such a space.

In an embodiment of a system according to the invention, the adhesive contact is a result of preheating a surface of a second layer, pressing that preheated surface against a surface of the first layer, and then letting the surfaces, which are pressed against each other, cool down. Advantageously, use is made of the nature of the second layer in the preparation of such a multi-layered structure. As will further be described below in a more detailed description, of the invention, such a multi-layered structure can act as a so-called bridge bearing, which can carry loads of 12000 kg per m².

In an embodiment of a system according to the invention, the polymer is a cross-linkable polymer. This allows for a further improvement of the mechanical properties of the second material. In essence, the second material may then as a result of a further rise in temperature adopt a rubber-like nature, and as such improves it stiffness. Consequently, it remains possible for the second material to continue suppressing expansion of the fire resistant elastomeric foam. Preferably, the second material comprises a vulcanizing agent that is activated at a temperature above 140° C.

In an embodiment of a system according to the invention, the second material comprises at least one component that causes the second material to thermally expand in a relatively low predetermined temperature range, of which a lowest temperature is above a temperature at which the transition into an adhesive is exhibited. Advantageously, the counter-pressure provided by the second material against the expansion of the fire resistant elastomeric foam can be maintained and even enhanced when the system is exposed to high temperatures. In other words, when the temperature rises and the pressure in the closed-cell structures increases and comes close to the bursting pressure of these closed cells, the second material will more strongly suppress such expansion of the closed cells, as the second material will expand itself. It follows that the insulating capacity of the system can be maintained for a longer period of time, even under the thermally more severe conditions.

Preferably, the at least one component is a thermally expandable graphite. That graphite is preferably a pH-neutralized graphite.

The invention further provides a multi-layered structure for filling a space or gap confined by construction elements, for resisting the spread of a nearby fire through the space or gap and for providing mechanical stability between the construction elements. The structure comprises: at least two first layers of a first material which comprises a fire resistant elastomeric foam having a closed-cell structure; and at least one second layer of a second material adhesively sandwiched between two first layers so that the first and second layers extend parallel to each other. The second material comprises a polymer and is stiffer than the first material.

The multi-layered structure is a prefabricated passive fire resistant system which offers the advantage the layering itself does not have to take place at the construction site. This prefabricated multi-layered structure offers immediately the mechanical stability as it does not have to be built up layer by layer. Furthermore, there is no need to wait for a nearby fire, or to deliberately apply heat locally, to ensure that the second layer sandwiched between the first layers will adhesively bond to these first layers. The manufacturer of the multi-layered structure will, under carefully controlled circumstances, have ensured that optimal bonding between these layers has already taken place. It is possible to cut the prefabricated multi-layered structure on a construction site, so that it will be locally tailored for fitting in a space or gap of concern. However, it is of course also possible that the manufacturer produces the multi-layered structures in a predescribed dimension, so that even any cutting can be avoided at the construction site.

Such a multi-layered structure can act as a bridge bearing, and carry a load of 12000 kg per m², and accept a compression of about 40% without failure of the multi-layered structure.

The invention will be further explained with reference to the non-limiting drawing, which shows in:

FIG. 1 a first embodiment of a system in accordance with the invention as positioned within a space or gap confined by construction elements;

FIG. 2 a second embodiment of a system in accordance with the invention as positioned within a space confined by a coaming situated in a metal construction wall;

FIG. 3 a third embodiment of a system in accordance with the invention; and

FIG. 4 the third embodiment as compressed in a direction perpendicular to the first and second layers.

In the drawing like parts are referred to by like references.

FIG. 1 shows a wall 1 built up from brick or concrete stones 2. In the wall 1, a window-type opening is situated. This window-type opening is considered to be an example of a space or gap confined by construction elements. That space or gap is filled with a passive fire resistant system according to the invention. The system comprises a number of first layers 3 of a first material which comprises a fire resistant elastomeric foam having a closed-cell structure. An example of such an elastomeric foam is described in WO2004/096369. The Applicant sells such a foam under the trademark name Actifoam.

The phrase “having a closed-cell structure” is understood to mean a cell structure in which at least 60%, but more preferably at least 75% of the cells are closed. This provides good thermal insulation.

The system further comprises a number of second layers 4 of a second material. The first and second layers 3, 4, extend parallel to each other. The second material comprises a polymer and each second layer 4 has surfaces which, as an initial response to a rise in their temperature from room temperature, exhibit a transition into an adhesive. The second material is stiffer than the first material. An example of the second material is described in WO2009/090247, in which the second material is described as the material of which a device is made, referred to in WO2009/090247 as device 6. the Applicant sells that material under the trade name RISE Ultra. The polymer is preferably a cross-linkable polymer. The polymer may be an EPDM, or preferably an ethylene acetate polymer (EVA). The second material preferably comprises a vulcanizing agent that is activated at a temperature above about 140° C.

As shown, it is possible that also each first layer 3 is sandwiched between two second layers 4 of the second material. In this respect, FIG. 1 shows a second layer 4 at the very bottom of the space that is filled by the fire resistant system according to the invention, as well as at the top thereof. Furthermore, also two layers of the second material are positioned vertically between the horizontally positioned layers and the vertical inner wall of the space. These second layers are referred to as second layers 4 a. The second material may comprise at least one component that causes the second material to thermally expand in a relatively predetermined temperature range, of which the lowest temperature is above the temperature at which the transition into an adhesive is exhibited.

Also the first material may comprise at least one component that causes the first material to thermally expand in a relatively high predetermined temperature range, of which the lowest temperature is above a temperature at which the surfaces of the second material exhibit a transition into an adhesive and is about at the temperature at which the vulcanizing agent is activated. Such a component may for both the first material and the second material be a thermally expandable graphite, which can be commercially obtained for expansion within different temperature ranges. The graphite is preferably pH-neutralized graphite. The first material may further comprise at least one crust-forming fire retardant component, for example, melaminephosphate. For possible compositions of the first material, reference is further made to WO2004/096369.

Each of the first layers has a thickness within the range varying from 1-4 cm, preferably within a range varying from 2-3 cm, even more preferably is about 2.5 cm. As shown, the thickness is preferably constant along the first layer. It is possible to make first layers for instance with a thickness of 1 cm, 1.5 cm, 2.0 cm, etc.

The second layer has preferably a thickness within the range varying from 1-4 mm, preferably from 2-3 mm, and even more preferable is about 2.5 mm.

In the event of a nearby fire, the temperature on the side of the wall closest to that nearby fire will rise. It is expected that the fire resistant system will be heated up by the hotter air. This will form the main source of heat input into the fire resistant system. In other words, heat transfer from the wall to the fire resistant system is considered to be negligible in this case.

The fire resistant system, particularly due to the cell structure in the first material will provide excellent heat insulation and inhibits the transfer of heat from the side exposed to the nearby fire to the side of the wall further away of the nearby fire. Further below, the side which is more directly exposed to the nearby fire is referred to as the exposed side. The side not directly exposed to the nearby fire, is further down referred to as the “unexposed side”.

Due to the rise in temperature the surfaces of the second layer will exhibit a transition into an adhesive and as such become adherent to the surfaces of the first layer. Although the heated gas in the closed cells will cause the pressure in those cells to rise, expansion of those cells, let alone bursting of the cells, will be suppressed by the adhesion of cells to the stiffer second layer. In other words, as the second material is stiffer than the first material, any deformation of the first material close to positions where the second material adheres to the first material will be suppressed. This lack of deformation of cells adhering to the second layer is in effect illustrated in FIG. 4.

As explained, expansion of the closed cells in the first material, is counteracted, to an extent. The bursting pressure of the cells is unlikely to be reached and the perfect insulation formed by the first material will continue to be present. As the first material remains in an insulating state, the layers of the second material, particularly “deeper” into the system, will not increase much further in their temperature and thus remain stiff. The mechanical stability is thus also maintained.

The upper end bottom second layer and the vertically positioned layers 4 a may reach a temperature at which the transition into an adhesive occurs. This ensures that the system will be “glued” into the opening.

Even though a response of the passive fire resistant system concerns a mechanism that aims at maintaining the state of the system, a part of the system that is more directly and closely exposed to a nearby fire, i.e. the part that is not insulated from the nearby fire, will experience a very high rise in temperature. Due to the crust-forming fire retardant component in the first material, such a crust will however be formed at the exposed side of the fire resistant system. At such high temperatures, also the thermal expansion of the second material will take place. The second material expands toward the heat source, offering further protection for the passive fire resistant system, between the layers of the crust formed by the first material.

The inventor found after exposure for more than one hour to a nearby fire that the temperature of the fire resistant system at the unexposed side, had only risen by 2° C. On the exposed side, a couple of mm of char had been formed. When the exposed side was then subjected to a so-called regular hose stream test (a 6 bar water hose stream directed at the passive fire resistant system at the exposed side) from a predescribed distance of 6 m, there was not any leakage of water through the passive fire resistant system from the exposed side to the unexposed side. Applying a more severe hose stream test from only 4 m distance with full load resulted in removal of the char layer of the fire resistant system. The passive fire resistant system could only be removed as a single unit by cutting it out of the opening in the wall, as all layers had clearly laminated to each other, particularly at the exposed side.

FIG. 2 shows a passive fire resistant system in accordance with the invention as positioned within a so-called coaming 5 made of metal and welded against a metal construction element, such as a metal wall 6. The system itself is further as the system described with reference to FIG. 1, although the number of layers applied in the coaming 5 is visibly less than the layers applied in the opening shown in FIG. 1. Upon exposure to a nearby fire, heat input into the passive fire resistant system will now occur via two different routes.

There is a direct route formed by hot gas directly “contacting” the passive fire resistant system, and an indirect route formed by transfer of heat from the equally heated metal coaming 5 and metal wall 6 into the passive fire resistant system. The most upper, most lower and vertical second layers 4 a, particularly toward the exposed side, reach a temperature that is far higher than the temperature at which the transition into an adhesive occurs. At those positions, the second material starts to thermally expand and starts to form a cross-linked material as the vulcanizing agent will have been activated. This phenomenon may clamp the system with the space or gap and suppress the expansion of the first material. Again, at the side that is directly exposed to heat, i.e. that is not insulated by the fire resistant itself, the second material will expand toward the source of heat, and the first material will form a crust. However, the temperature reached at positions deeper within the fire resistant system is higher than the temperature reached for the fire resistant system placed in a wall 1 as discussed above in relation to FIG. 1. Consequently, the first material will expand into the direction of least resistance, which in this case is toward the unexposed side. Parts of the most upper, most lower and vertical layers 4 a which are situated at the unexposed side may only reach a temperature at which the transition into the adhesive occurs. This will assist in a fixing of the passive fire resistant system within the coaming 5, particularly toward the unexposed side. However, the inventor observed that under these circumstances expansion of the system occurred in a direction toward the unexposed side. Even though under these circumstances the passive fire resistant system has a more vigorous response, during a “fire load” lasting for two hours, the mechanical stability was not lost and no smoke was formed at the unexposed side.

FIG. 3 shows a sandwich structure for filling a space or gap confined by construction elements, for resisting the spread of a nearby fire through the space or gap. The structure comprises four first layers 3 of a first material which comprises a fire resistant elastomeric foam having a closed-cell structure; and three second layers 4 of a second material. Each second layer is adhesively sandwiched between two first layers. The first and second layers extend parallel to each other. Such a multi-layered sandwich structure may be formed by heating up a layer of the second material to about 100° C. at which surfaces of the second layer turn into a very adhesive. Such layers, preferably about 2.5 mm thick, are then under pressure sandwiched between two first layers. These multi-layers are then cooled down.

The second material comprises polymer and is stiffer than the first material. As explained, in this example, each second layer is adhesively sandwiched between two first layers 3 by adhesive contact of the second layer 4 with each of these first layers 3. A number of first layers 3 are equally adhesively sandwiched between two second layers 4 of the second material. Those first layers 3 are adhesively sandwiched between two second layers 4 of the second material by adhesive contact of these second layers 4 with the first layer 3. The adhesive contact discussed above may be a result of preheating a surface of a second layer, pressing that preheated surface against a surface of a first layer 3 and then letting these surfaces which are pressed against each other cool down. The first layers 3 and the second layers 4 are as those described in relation to FIG. 1 and 2.

FIG. 4 shows how such a sandwich structure responds to a compression into a direction that is perpendicular to the direction of the layers 3, 4. The direction of compression is shown by the arrows C. Although the thickness of each first layer 3 is reduced, and the elastomer foam expands in the configuration shown in FIG. 4 somewhat sideways, it is clear that at the contact surfaces between the first layers 3 and the second layers 4, sideway expansion of the first layers 3 is suppressed. The structure acts as a so-called “bridge bearing”. For a sandwich structure shown in FIG. 4, a much higher compression force is needed to obtain a compression of say 40%, than the compression force needed for obtaining a compression of 40% in a stacking of four first layers 3, without the sandwiching of the second layers 4. The multi-layered sandwich structure can carry a load of up to 12000 kg per m². Clearly, this prefabricated structure can offer direct mechanical stability where needed. As explained above, the response to exposure to a nearby fire, is aimed at maintenance of the original state for as long as possible, and for a part of the system, as large as possible. The same applies to the mechanical stability.

Also, such a prefabricated multi-layered sandwich structure is preferably applied with second layers at the top and the bottom as well as sideways oriented in a vertical direction (see for example FIG. 1 and FIG. 2).

In summary, both the passive fire resistant system as well as the prefabricated multi-layered sandwich structure are applied with these extra second layers of second material at the bottom and at the top, as well as sideways in a vertical direction. So far, this has been to deliver an optimal effect. The second layers of second material within the multi-layers are thermally insulated, so that the mechanical stability at those positions is maintained. The layers at the bottom, top and sides of the system and structure are, particularly at the exposed side, not thermally insulated, and will turn into an adhesive, fixing the system and structure within the spaces or gaps against the construction elements by which these spaces or gaps or confined. Parts of the system and structure that are directly exposed to a high rise in temperature trigger the crust formation of the first material and the thermal expansion of the second material toward the heat source. It forms a relatively thin but effective shield, ensuring that the part of the system and the structure further away from the heat sources and insulated by the system and structure itself, maintain their original mechanical and thermal insulation properties.

The invention is not limited to the examples and embodiments discussed above. Alterations and modifications are possible. It is, for instance, possible to design a multi-layered structure, to be prefabricated or to be put together on the construction site, wherein the first layers have a thickness that varies with their position within the structure and wherein the second layers have a thickness that varies with their position within the structure. The contribution of the various layers can then be optimized so that the overall response of the system even further meets the objectives outlined earlier on.

Such alternative embodiments are each understood to fall within the framework of the invention as defined by the appended claims. 

1. A passive fire resistant system for filling a space or gap confined by construction elements, for resisting the spread of a nearby fire through the space or gap, wherein the system comprises: at least two first layers of a first material which comprises a fire resistant elastomeric foam having a closed cell structure; and at least one second layer of a second material sandwiched between two first layers, the second material comprising a polymer and each second layer having surfaces which, as an initial response to a rise in their temperature from room temperature, exhibit a transition into an adhesive, the first and second layers extending parallel to each other, the second material being stiffer than the first material.
 2. A system according to claim 1, wherein the at least one second layer is adhesively sandwiched between two first layers by adhesive contact of the second layer with each of these first layers.
 3. A system according to claim 1, wherein each first layer is sandwiched between two second layers of the second material.
 4. A system according to claim 3, wherein each first layer is adhesively sandwiched between two second layers of the second material by adhesive contact of these second layers with the first layer.
 5. A system according to claim 2, wherein the adhesive contact is a result of preheating a surface of a second layer, pressing that preheated surface against a surface of a first layer, and then letting these surfaces which are pressed against each other cool down.
 6. A system according to claim 1, wherein the polymer is a cross-linkable polymer.
 7. A system according to claim 6, wherein the second material comprises a vulcanizing agent that is activated at a temperature above about 140° C.
 8. A system according to claim 1, wherein the polymer is EPDM or EVA.
 9. A system according to claim 1, wherein the second material comprises at least one component that causes the second material to thermally expand in a relatively low predetermined temperature range of which a lowest temperature is above a temperature at which the transition into an adhesive is exhibited.
 10. A system according to claim 7, wherein the first material comprises at least one component that causes the first material to thermally expand in a relatively high predetermined temperature range of which a lowest temperature is above a temperature at which the surfaces of the second material exhibit a transition into an adhesive and is at about a temperature at which the vulcanizing agent is activated.
 11. A system according to claim 9, wherein the at least one component is a thermally expandable graphite.
 12. A system according to claim 11, wherein the graphite is a pH-neutralized graphite.
 13. A system according to claim 1, wherein the first material comprises at least one crust-forming, fire retardant component.
 14. A system according to claim 1, wherein each of the first layers has a thickness within a range varying from about 1-4 cm, preferably within a range varying from 2-3 cm, even more preferably is about 2.5 cm.
 15. A system according to claim 1, wherein the second layer has a thickness within a range varying from 1-4 mm, preferably 2-3 mm, and even more preferably is about 2.5 mm. 